1. Field of the Invention
The present invention is related to engine construction technologies and can be applied in spark ignition gas piston engines operating mainly on lean mixtures of hydrocarbon gases.
2. Description of the Related Art
A gas piston engine with precombustion chamber torch ignition is known, and comprises a cylinder, a cylinder head with the main spark plug located along the cylinder axes, a precombustion chamber with an additional spark plug and a gas inlet valve (see e.g., RU Patent No. 2080471) (Reference [1]). However, a drawback of such design is complexity and high cost of the fuel system. Nevertheless, this design has been implemented in construction of powerful engines, mainly, engines producing over 2 megawatts.
In another design (see e.g., U.S. Pat. No. 5,611,307) (Reference [2]), the rich hydrogen-air mixture goes through a pilot-actuated valve to a precombustion chamber, with the mixture, having been ignited by a spark plug, enflaming the main lean fuel-air mixture in the engine cylinder. This method is more efficient compared to Reference [1], but, at the same time, is much more complicated, since it requires two different kinds of fuel, where the second kind of fuel consists of hydrogen incoming as a hydrogen-air mixture through a pilot-actuated valve. In one of the claimed variants, the possibility of the lean fuel-air mixture reforming in the precombustion chamber by means of a catalyst with electric heating is mentioned. In case of hydrogen shortage, the hydrogen is provided from outside as a hydrogen-air mixture incoming through the pilot-actuated valve. However, the design in Reference [2] is probably not actually workable because the heating unit consisting of a substrate-electric heater and a mesh-catalyst are located inside the precombustion chamber and cannot withstand the destructive impact of cyclic pressure and temperature jumps from 0.1 to 11 MPa and from 50 to 1700° C. every 80 milliseconds at the engine rotation frequency of some 1500 rpm. The method has not found much use.
Russian Patent No. 2099549 (Reference [3]) describes a method of igniting a fuel-air, mainly a lean, mixture in an internal combustion engine having a main combustion chamber and an ignition chamber (hereafter, this term is used as a synonym for precombustion chamber), where the method comprises the following stages: inletting, at the compression stroke, a fuel-air mixture from the main combustion chamber to the ignition chamber, igniting the fuel-air mixture, and emitting the inflamed torch to the main combustion chamber at the beginning of the expansion stroke. Here, the main distinctive feature of the method (see FIG. 1) is that the inlet of the fuel-air mixture from the main combustion chamber 1 to the ignition chamber 4 is performed along its central axis through gas-dynamic sensors, where at least one sensor 8 has the one-way throughput capability towards the ignition chamber, whereas the outlet of the ignited torch from the ignition chamber to the main combustion chamber goes along its periphery through the gas-dynamic sensors 9, of which at least two sensors have the one-way throughput capability towards the main combustion chamber and the fire jets are directed towards the conditional circle of the mass centre for a given volume of the main combustion chamber.
To embody the method of Reference [3], a design of several parts of the modified engine was also claimed. FIG. 1 shows such a conventional design, where 1—is the combustion chamber, 2—is the piston, 3—is the engine body, 4—is the ignition chamber, 5—is the ignition device, 8—is the one-way inlet channel (sensor), 9—a one-way outlet channel (sensor). In this publication, only one kind of fuel is used, and its inventors stated that this technical solution offers high reliability and efficiency while consuming lean fuel-air mixtures; however, so far no information is available regarding general application of such technology. The main drawback of the described conventional methods are complexity and high precision requirements to manufacture and process the device components, and also apparently relatively unimpressive performance characteristics.